Fluid control for inert gas blanketed arc welding



June 6, 1950 E. R. BEHNKE ETAL 2,510,207

FLUID CONTROL FOR INERT GAS BLANKETED ARC WELDING Filed May 4, 1949 V Warer INVENTORS L A T Y L P P 4 -U 45 RR m0 P llk[ EDWARD R. BEHNKE STANLEY H. ROYER ATTORNEY ConTro l Box Patented June 6, 1950 FLUID CONTROL FOR INERT GAS BLANKETED ARC WELDING Edward R. Behnke, Newark, and

Stanley H.

Boyer, Elizabeth, N. J., assignors to The Linde Air Products Company, a corporation of Ohio Application May 4, 1949, Serial No. 91,246

6 Claims.

This invention relates to fluid control for inert gas blanketed arc welding torches, and more particularly to automatic control of the flow of inert gas to welding torches in which an annular stream of inert gas flows along the electrode to blanket the arc and molten portions of the work during the welding operation.

It has been customary to manually cut off the flow of inert gas as soon as the weld is completed. This leaves the highly heated electrode unprotected from oxidation by the atmosphere air, resulting in short life of the electrode.

It is therefore the main object of the present invention to provide an automatic control for continuing the flow of inert gas until the electrode has cooled below oxidation temperature.

A large proportion of these torches are water cooled, and flow of cooling water during nonwelding periods may be costly. More important, moisture will condense on equipment during nonwelding periods when atmospheric temperature and humidity are high, and cooling water temperature is low.

It is therefore a further object of the present invention to provide an automatic control for cutting oil the flow of cooling water after the electrode has cooled below oxidation temperature.

According to the present invention, a valve is provided for controlling the supply of gas to the conduit which passes gas to the torch nozzle, operating means are provided for the valve, and means responsive to voltage change in the welding circuit are provided for actuating the valve operating means. A similar valve and operating means are provided in the cooling water supply conduit, and actuated by the same or similar voltage responsive means.

Other objects and features of novelty will be apparent from the following description and the accompanying drawing, in which the single figure is a wiring diagram of the control device according to the present invention.

As shown in the drawing, the torch T comprises an electrode E surrounded by a nozzle N to which inert gas such as helium or argon is supplied by a conduit A controlled by an argon valve 15. A motor driven welding generator G energizes the welding circuit which passes through the electrode E and the work W when an arc is struck. The torch T has a cooling jacket J to which cooling liquid is suplied by a conduit L controlled by a water valve iii. The operation desired is controlled by a control box B, energized through a line switch S. The control box B comprises a timer starting relay I 0, a holding relay l2, a

valve closing timer l4, and a shut-off relay H. The timer starting relay has a normally open switch l8 and a normally closed switch 29. The coil of the relay IE! is shunted across the terminals of the welding generator in series with an adjustable resistance 22 which is adjusted to cause the relay to respond to increase from are voltage to open circuit voltage.

The holding relay [2 has a normally open switch 23, and a coil which is in series with the switch 2| of the starting relay H3. The shut-off relay I! has a normally open switch 24 and a coil in series with an adjustable resistance 25. The shut-off relay i'l prevents the argon and water valves from remaining open when the welding generator is turned off and the control unit is left The timer [4 has a normally closed switch 21, and a motor 28 which is in series with the switch is of the starting relay Hi. The motor 28 drives a cam 29 through a gearing or escapement 38, which after the time period for which the timer is adjusted, causes the cam to open the switch 21.

For the purposes of the main object of the present invention, it will be assumed that the apparatus is in operation, the welding arc is established, and welding is in progress. When the welding arc is extinguished by removing the electrode from the workpiece, the welding circuit voltage increases from are voltage to full open circuit voltage. This condition energizes the coil of starting relay I!) which closes its switch l8 and opens its switch 20. Closing switch l8 energizes the timer motor 23 which starts the gearing or escapement 39 running, but switch 21 remains closed for the time delay period. Through switch 21 the coil of relay i2 remains energized, and its switch 23 closed, so that notwithstanding the opening of switch 28, the argon valve I5 and the Water valve l6 remain open, being energized through switches 2'! and 23.

At the expiration of the time delay period, the cam 29 opens the switch 21, which opens the circuit for the argon valve 15 and the water valve [6, which return to their normally closed positions.

The sequence of operations for starting up, welding, and stopping will now be described in chronological order.

When all of the apparatus is connected as shown in the drawing, but the welding generator is not running and the control box line switch S is open, the relay H is de-energized with its switch 24 open, the relay is is de-energized with its switch l8 open and its switch 20 closed. The

switches 21 and to close its switch 23. 1 When the welding; generator is turned on, the relay ll is energized through the resistance to close its switch 24, and the relay H] is energized to close its switch it and open its switch 7283., The.

opening of switch Zil has no effect becauseait is. in parallel with switch 23 of holding relay I2.

Closing switch 08 energizes the timer M'- and starts its motor running, but the switch 21. re-- mains closed for the time delay period.

If nothing more is done before the time -.period expires, the motor opens the switch 21, which de-energizes the relay 12, opens the switch 23,:

which closes the argon valve 15 and the water valve 16.

It is undesirable to establish the welding iarc' until-the iargon valve has beenturned on long-- enough ate purge the line and blanket the; elec-. trade with ;.full -;argon-fl0w-, allbefore the elec trode-can-get as hotas it'would if the full'arcweretstrucke For thisz-purposethe welding :elec

trode is touched to or barelyscratched on the workpiece. This causes'the open circuit voltage tordecrease tosome value approaching arc volt age.-

theiargon valve andthe water-valve.

The ewelding electrode is immediately removed This de-energizes the starting relay lfl; opening .its switch 18,. which de-energizesthe timer mQtor-ZBand-closesswitch 21. The starting relay Ill also. closes switch 2!]; which opensfrom the workpiece, before a welding arc can betestablished. which causes the welding circuit :to

returnto full open circuit voltage: This energizer the starting-relay m closing switch is whichen ergizesthetimer motor 28 and starts it running.

After this preliminary scratching- 'orpurging; step,- the electrode is returned-and the'welding arcisestablished to begin welding,. by touching the. electrodetto theworkpiece.-

This decreases thempen circuit voltage to are voltage, opening relay 1 it, and de-energizing the timer motor;- 28' which. automatically resets. During the welding operation, therelay l'l'remains energized with its,

switchs-2 l closed; the relay is remains-de-e-nerclosed, the.-,relay I 2 remains energized withits switch. 23 ..closed,--andthe argon valve andwatervalve .l 5 remain open.

When thewelding arcis extinguished by removingtheelectrodefrom proximity to thG-,.V0fkr piece,-the relay I8). is energized to closeits switch l8, energize the-timer l4 and start itsmotoi: 23 .7

-60 gized with its switch it open and itsswitch 2 running. At theexpiration of the: time delay period the timer M opensits switch ZTwhich closes the argon valve l5-andtl1e water valve 16.

What is claimed is:

1..In a gasbIanketed arc welding apparatus comprisinga torchhaving anlelectrode anda,

nozzle, an electric ,circuit for passingweldingcurrent'through said electrode and the work, a 0011:?

duit for passing gas to said nozzle, a coolingjacket' for said torch, and a conduit for supplying cooling liquid fluid to said jacket, the improvement which comprises avalve for controllingthe sup ply of'fluidto-one of said conduits, means for operating said valve, and means responsive to voltagechangein saidvelectric circuitfor actuating said valve operatingmeans.

2. In a gas blanketed arc welding apparatus comprising a torch having an electrode and a nozzle, an electric circuit for passing welding current through said electrode and the work, and a conduit for passing gas to said nozzle, the im provement which comprises a valve for con trollingthe .supply of gas tosaid conduit, means for operating said valve; and means responsive to voltage change in said electric circuit for actuating said valve operating means.

3. In a gas blanketed arc welding apparatus comprising atorch having an electrode and a nozzle, an electric circuit for passing welding current'fthroughsaid Ielectrode and the work, a conduit 'forpassinggas to said nozzle, and a conduit for supplying cooling fluid to the torch, the improvement which comprises a valve for controlling the supply of cooling fluid to said conduitgmeans for operating said valve, and means responsive to voltage change in said electric circuit-for actuating said valve operatingmeanszr;

ii- In algae-blanketed arc welding apparatus: comprising-,a torch'havingan electrode and-7 a nozzle an electric circuit -for "passing vwel'ding; current through said electrode and the'work,;-and" a conduit for passing gas to said; nozzle, thetime:

provement which comprises a '-valv,e for: cone trollingthesupply of gas to said conduit, means responsive to arcvoltage when an arc. 'iSiStlllCk"' between saidelectrode and the work .for opening. said valve a'time delay device for effect-ingtclose ing said valveandmeans responsiveto .opencin cuit voltagewhensaid electrode is removed from the-work-to extinguish'the arc for setting said .time delay device to close said valve a-predetermined time delay: interval after the "arc'is. exev tinguishedr 5. In a gas blanketed arcwelding apparatus comprising -a-torch having an electrode and a nozzle, anrelectric circuit for" passing welding; currentthroughzsaid electrode and the work, and.

a conduit for; passing gas to said nozz-latheima provement which comprises a valve for--con= trolling thersupply of gas to said-conduit, means responsive to are voltage when the electrode is. touched-tothe work momentarily without heateing the electrode to oxidation temperature"; for

opening sa-idvalva said valve opening means being further responsive-to arc voltage when 3." welding-arcis struck for maintaining said valve open duringthe welding operation.-

fis-In-a gas blanketed arc welding apparatus comprising attorch. having an electrode. and a nozzle, an electric: circuit for passing welding current through said electrode and the work, and a conduit for passinggas to said nozzle, the im-- REFERENCES CITED The follo'wing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,329,904.. Howard Sept. 21, 1945' 

